Let's start with stating that the theory of orbital changes as a primary driver as if it were a demonstrated fact, and then move on to wondering where you came up with cutting the Antarctic value in half, and then in half again.

I will agree that the orbital variation seems to have a part to play, but I will not agree that its role has been demonstrated, but even assuming that, where do you come up with the rest of your statement?

How many factors can influence the climate? The clear cyclical glaciation - intermediate - glaciation signal over the last 2 million years or so match the Milankovich cycles to such a degree that I think it is safe to say that orbital variation is the accepted explanation for the warming during intermediaries and cooling during glaciations.

The Vostock core shows that in the Antarctic, the four last intermediary temperature maxima reached some 5 degrees C above present (which is usually centered on 1970 in palaeoclimate terms), with our Holocene climate maximum being slightly lower, at some 3-4 degrees C above present. (Note that the Vostock core was drilled in 1995, but meaningful data can only really be extracted from ice that is quite old, on a scale of centuries if not millennia).

Global temperature during the Holocene show that the Holocene climate maximum was less than 1 degree C warmer than present time (i.e. 1970) - which seems to indicate that the maximum at Antarctica was some 4 times higher than the global maximum.

Research in the northern hemisphere (mainly Europe) seems to indicate that the Holocene maximum was much stronger the closer to the (North) pole one goes. So the Holocene maximum (and other intermediary maxima) may well have been exaggerated towards the poles.

Previous rapid warming events over the last 2 million years, when going from glaciation to intermediary, were caused by orbital change with added feedback from CO2 and methane. The current rapid warming goes against the effects of orbital change (the climate should be cooling rapidly) and is mainly caused by a large increase in CO2, so it is reasonable to expect the pattern of warming being different this time.

"more rapid or extensive warming in scenarios such asRCP8.5 would be outside the experience provided by past interglacialperiods reviewed here. Such a pathway into conditions withoutwell-studied precedent would be inherently risky for human societyand sustainable development."

...Previous rapid warming events over the last 2 million years, when going from glaciation to intermediary, were caused by orbital change with added feedback from CO2 and methane. The current rapid warming goes against the effects of orbital change (the climate should be cooling rapidly) and is mainly caused by a large increase in CO2, so it is reasonable to expect the pattern of warming being different this time.

I will quibble only with the parenthetical "the climate should be cooling rapidly" due to Milankovich forcing. Without AGW, I understand Earth's climate would be cooling slowly during my lifetime (that is, on a human scale), although I'll accept "rapidly" in the geological scheme of things.

...Previous rapid warming events over the last 2 million years, when going from glaciation to intermediary, were caused by orbital change with added feedback from CO2 and methane. The current rapid warming goes against the effects of orbital change (the climate should be cooling rapidly) and is mainly caused by a large increase in CO2, so it is reasonable to expect the pattern of warming being different this time.

I will quibble only with the parenthetical "the climate should be cooling rapidly" due to Milankovich forcing. Without AGW, I understand Earth's climate would be cooling slowly during my lifetime (that is, on a human scale), although I'll accept "rapidly" in the geological scheme of things.

Yeah well that partly depends on how you look on the early anthropocene hypothesis, Holocene was exeptionally long for an interglacial so it could be a thousand year plunge to the next glacial would be on already. Agree that a thousand years is still quite slow for a human timescale, f.e. I don't even know any of my ancestors that far back . But some people know, so maybe this is rapid.

magnamentis

this is on topic IMO, or don't you think that looking into the past will help to understand mechanisms as well as the relevance of positive and negative feedbacks as well as seeing repeating patterns that help to come to better conclusions?

if we have an opinion about when the arctic will become ice-free it's good practice to underline our opinion with know facts from the past and weigh them in the process, else we can play the lottery.

this is on topic IMO, or don't you think that looking into the past will help to understand mechanisms as well as the relevance of positive and negative feedbacks as well as seeing repeating patterns that help to come to better conclusions?

if we have an opinion about when the arctic will become ice-free it's good practice to underline our opinion with know facts from the past and weigh them in the process, else we can play the lottery.

Given the recent rapid melt in the Arctic despite having a season not overly conducive to melt, I think a summer BOE event could be just one disastrous melt season away. If we were to get 2007 conditions next year, we could see our first BOE event IMHO.

A BOE in the summer does not, however, guarantee another BOE in the following summer. As we saw in both 2007 and 2012, the melt season minimums bounced back the following seasons, although at a new lower level. I would expect the melt seasons after the 1st BOE to exhibit similar behaviors, bouncing back to another new, lower level.

magnamentis

Given the recent rapid melt in the Arctic despite having a season not overly conducive to melt, I think a summer BOE event could be just one disastrous melt season away. If we were to get 2007 conditions next year, we could see our first BOE event IMHO.

A BOE in the summer does not, however, guarantee another BOE in the following summer. As we saw in both 2007 and 2012, the melt season minimums bounced back the following seasons, although at a new lower level. I would expect the melt seasons after the 1st BOE to exhibit similar behaviors, bouncing back to another new, lower level.

you "if then" assumption is of course entirely correct.

what remains to assess is how big the possibility for i.e. a 2007 melting season currently is, given the vast increaso of humidity that will most probably most of the coming summers lead to extensive cloud cover which makes it much more probably that the last 2 summers will be kind of a new normal.

this of course does by no means exclude the possibility for exceptions and outliers, hence, as mentioned you "if then" the way you wrote it is perfectly true, just wanted to add probability of such and "if then" scenario to the discussion.

The decrease in NSIDC minimum extent between 2007 and 2012 was 0.76 (million square km) from 4.15 to 3.39.

I would suggest, therefore, that we might be more than one super-melt summer away from a summer below 1 million square km.

As to the clouds and humidity, the dominant factor here is atmospheric pressure. Under a stable high pressure system you have descent of the air, which warms as it descends (due to the increase in pressure, it warms a lot), and so this will tend to keep the clouds away.

Humidity in the boundary layer can create fog temporarily in these conditions, but the 24-hour nature of the summer Arctic sun will tend to militate against that too.

The decrease in NSIDC minimum extent between 2007 and 2012 was 0.76 (million square km) from 4.15 to 3.39.

I would suggest, therefore, that we might be more than one super-melt summer away from a summer below 1 million square km.

Perhaps. But in 2012 and especially in 2007, there was a large amount of very thick MYI that had to melt. Now. Not so much.

The step function we see in this SIE chart which occurred in 2007 is a direct result of the massive destruction of thick MYI. 2007 essentially set a new floor for minimums by causing the Arctic to enter into a new regime where MYI made up a much smaller portion of the Arctic. This has set the stage for a catastrophic drop whenever we have another season conducive to melt.

We see the exact same impact on volume. We simply have far less volume to melt and a disastrous melting season will have a much more damaging impact.

Given the recent rapid melt in the Arctic despite having a season not overly conducive to melt, I think a summer BOE event could be just one disastrous melt season away. If we were to get 2007 conditions next year, we could see our first BOE event IMHO.

A BOE in the summer does not, however, guarantee another BOE in the following summer. As we saw in both 2007 and 2012, the melt season minimums bounced back the following seasons, although at a new lower level. I would expect the melt seasons after the 1st BOE to exhibit similar behaviors, bouncing back to another new, lower level.

Strongly agree. As I often say when talking to newcomers about this topic: There's a very well established trend/signal that's combined with a lot of noise in the form of yearly weather variations. We're about to enter a period where a BOE (or lack thereof) in any given year is a result of how much noise and in which direction we see.

I wouldn't be surprised to see a BOE in the next year or two, only to not see another for five years, then get them two years running, etc.

I wouldn't be surprised to see a BOE in the next year or two, only to not see another for five years, then get them two years running, etc.

I'll pay attention to DMI 80N rather than extent, but once there is not enough ice to pin the temperature close to 0 in the Summer there won't be enough cold to keep the ocean from overturning and losing its protective fresh halocline layer. When there isn't enough ice to keep it cold in Summer it won't really get cold in Winter.

Shouldn't we be looking at the Hudson bay to go blue ocean year-long, long before the CAB does?!!

Actually, counter intuitively, the greater probability is that it will continue to freeze after the CAB becomes "ice free" - less than 1 million KM2 of ice in winter.

And I am pretty sure, that the Hudson Bay as well as the North Pole will always* freeze in winter. On the North Pole you have 180 days of no sunlight, that will always be much below zero, no matter what. Average temperature in Winter is around -30°C at the North Pole and -20°C over most of Hudson Bay. So even if temperaturs would raise globally by 15°C, it would still be well below freezing in many areas there and therefore ice would form.

I agree.

Even after a summer BOE, ice will still form in the Arctic during the dark, polar winter for many decades. This cover of FYI will look and behave differently, likely thinner due to warmer winters, more mobile even in the dead of winter and more susceptible to melt the following melt season. This is no different than what we are observing in the peripheral seas in the basin. The Beaufort and Chukchi froze late and the resulting ice was far thinner and, as can be seen this year, will melt out despite conditions not conducive to melt.

I'm quoting here from the Melt Season thread cuz it makes more sense to discuss here:

I idea that the north pole will freeze for over for at least the next new thousand years because it is dark for half the year doesn't hold up to scrutiny because there are already areas north of 80N that have gone the past year without any ice. Not only no ice, but very warm SSTs. The ocean will continue to warm. The atmosphere will continue to warm. The Atlantic will encroach and the ice will retreat.

Also, it is kinda a "humpty dumpty situation". Once the ice melts in the summer, there will be mixing. The salinity of the water nearest to the surface will increase and refreeze will be more difficult. The salinity around the entirety of greenland and west into the CAA has already started to show significant increase. Once the summer ice melts, its much more difficult for it to be put back together again.

This process will take several years, but there are so many forcing to hurt ice, and very few to help. A big one that is rarely discussed in the likely drastic increase of soot from increased wildfires north of 60N. Layer greenland and the remaining arctic ice with black particles and all the models and predictions go out the window. Thousands of years becomes decades.

If global temperature rise 15 degrees C, there WILL NOT be any sea ice in the northern hemisphere. And there WILL NOT be any humans in the northern hemisphere to pay attention.

EDIT: while i was posting this A Team posted something along the same lines in the Melt Thread, just 1000x more classy and science-like.

Shouldn't we be looking at the Hudson bay to go blue ocean year-long, long before the CAB does?!!

Actually, counter intuitively, the greater probability is that it will continue to freeze after the CAB becomes "ice free" - less than 1 million KM2 of ice in winter.

And I am pretty sure, that the Hudson Bay as well as the North Pole will always* freeze in winter. On the North Pole you have 180 days of no sunlight, that will always be much below zero, no matter what. Average temperature in Winter is around -30°C at the North Pole and -20°C over most of Hudson Bay. So even if temperaturs would raise globally by 15°C, it would still be well below freezing in many areas there and therefore ice would form.

I agree.

Even after a summer BOE, ice will still form in the Arctic during the dark, polar winter for many decades. This cover of FYI will look and behave differently, likely thinner due to warmer winters, more mobile even in the dead of winter and more susceptible to melt the following melt season. This is no different than what we are observing in the peripheral seas in the basin. The Beaufort and Chukchi froze late and the resulting ice was far thinner and, as can be seen this year, will melt out despite conditions not conducive to melt.

I'm quoting here from the Melt Season thread cuz it makes more sense to discuss here:

I idea that the north pole will freeze for over for at least the next new thousand years because it is dark for half the year doesn't hold up to scrutiny because there are already areas north of 80N that have gone the past year without any ice. Not only no ice, but very warm SSTs. The ocean will continue to warm. The atmosphere will continue to warm. The Atlantic will encroach and the ice will retreat.

Also, it is kinda a "humpty dumpty situation". Once the ice melts in the summer, there will be mixing. The salinity of the water nearest to the surface will increase and refreeze will be more difficult. The salinity around the entirety of greenland and west into the CAA has already started to show significant increase. Once the summer ice melts, its much more difficult for it to be put back together again.

This process will take several years, but there are so many forcing to hurt ice, and very few to help. A big one that is rarely discussed in the likely drastic increase of soot from increased wildfires north of 60N. Layer greenland and the remaining arctic ice with black particles and all the models and predictions go out the window. Thousands of years becomes decades.

If global temperature rise 15 degrees C, there WILL NOT be any sea ice in the northern hemisphere. And there WILL NOT be any humans in the northern hemisphere to pay attention.

EDIT: while i was posting this A Team posted something along the same lines in the Melt Thread, just 1000x more classy and science-like.

this is about the arctic, not about the north pole or any point above 80N

if we talk about the arctic being ice free i say that each warm current has it's cold counterpart and that in one part of the arctic (one side if you prefer) there will always be a lot of ice.

since we don't know how currents will change and develop under new conditons no-one can say which part but it probably won't be be pole itself but one of the seas attached to large continentals land masses.

before siberia for example will come up to -10C average from curretnly -40C (dunno exact numbers) it will take quite a while and those winds will blow over the ice exactly like the warm winds from another side.

hence even if the north pole will be ice-free all year, the arctic as a whole will not.

this topic is more about how big a picture someone is able or willing to think. most of the reasoning used here is cherry picked petty reasoning mostly forgetting an entire big chunk of the cake (story) simply to fit into whichful (sensational) thinking.

if the chucki and svalbard are ice free it is because there are opeings on both sides into huge oceans with huge amounts of heat stored while on the canadia and russian side this won't be the case.

since i opt for zero (close to zero) ice cover to name the arctic ice-free the arctic will hold ice in winter for a long long time.

those opting for the 1 million km2 as a threshold, which is arbitrary and counterintuitive to get an earlier headline, will see THEIR event earlier but even the million will be reach for a long time to come. don't forget we are over 10 million during winter now and don't tell me that we go from above 10 to below 1 million in a few years if ever.

EDIT:

we don't even know whether the so often mentioned warm currents that currently keep the so often mentioned svalbard ice-free most of the times will still exist in that are when the time has come.

after all it's well possible the the so called "gulf stream" will start to drop to the sea-flor much more south once the salinity of the arctic will be more impated by greenland melt and less saline water freezes much earlier, hence we don't even know whether freshwater supplies and lack of warm water supply could even increase ice cover during winter.

i don't really believe that but it's still possible, we simply don't know.

if we talk about the arctic being ice free i say that each warm current has it's cold counterpart and that in one part of the arctic (one side if you prefer) there will always be a lot of ice.

You've said it before, and I asked: Is that some sort of natural law? That each warm current has it's cold counterpart? How and why?

To me this indicates a lack of understanding of how the big warm surface currents and the big cold bottom currents are tied together: The real counterpart of any warm surface current is a cold bottom current.

The image shows warm and cold currents in the North-Atlantic, both surface and deep. The warm currents are all on the surface, while the cold currents (with the exception of the narrow one running down the east coast of Greenland) are deep currents.

magnamentis

if we talk about the arctic being ice free i say that each warm current has it's cold counterpart and that in one part of the arctic (one side if you prefer) there will always be a lot of ice.

You've said it before, and I asked: Is that some sort of natural law? That each warm current has it's cold counterpart? How and why?

To me this indicates a lack of understanding of how the big warm surface currents and the big cold bottom currents are tied together: The real counterpart of any warm surface current is a cold bottom current.

The image shows warm and cold currents in the North-Atlantic, both surface and deep. The warm currents are all on the surface, while the cold currents (with the exception of the narrow one running down the east coast of Greenland) are deep currents.

now i'd have to post a book to counter your statements, we'd have to go into density, salinity, when warm currents start to drop to the sea-floor to return south etc. but there are cold currents on the surface for sure, humbolt and many others, so the "all" is not correct and more time i'm not willing to spend on this topic. we can agree that we disagree and see what happens.

i tell you that none of us shall see an ice-free arctic in winter (arctic not north pole) and you have another opinion which to proof false would take years work of studies and combine them into an excerpt. this is just too much and won't change the future anyways, hence i propose to leave it at that for the moment, it simply doesn't matter who is right and the future will tell what is right/wil happen.

i tell you that none of us shall see an ice-free arctic in winter (arctic not north pole) and you have another opinion which to proof false would take years work of studies and combine them into an excerpt. this is just too much and won't change the future anyways, hence i propose to leave it at that for the moment, it simply doesn't matter who is right and the future will tell what is right/wil happen.

enjoy further

If I were to exclude certain areas, most notably the Hudson, would you still make that claim?

Suppose I posit that everywhere that is not very close to a cold continent will melt out soon (5 years) and stay melted out in the winter? What would you say about that?

Logged

magnamentis

i tell you that none of us shall see an ice-free arctic in winter (arctic not north pole) and you have another opinion which to proof false would take years work of studies and combine them into an excerpt. this is just too much and won't change the future anyways, hence i propose to leave it at that for the moment, it simply doesn't matter who is right and the future will tell what is right/wil happen.

enjoy further

If I were to exclude certain areas, most notably the Hudson, would you still make that claim?

Suppose I posit that everywhere that is not very close to a cold continent will melt out soon (5 years) and stay melted out in the winter? What would you say about that?

i see what you mean.

consequently if you exclude certain areas we shall certainly see certain areas going ice-free year round, i.e. i suspect that the pole will be much earler ice free in winter than hudson bay, just to take on your example, but then:

if we exclude areas we don't talk "arcitic" anymore and certainly the discussion is originally meant the for the arctic basin.

i know that we distinguis between arcitc basin, central arctic basin, arctic as to above tropic of cancer and arctic ocean as to the waters that freeze over.

IMO hudson bay except that it's freezing and connected to the big oceans does not even belong to the arctic. no matter what humans find as criteria, it's below the tropic of cancer almost entirely.

i know that my definitions don't count but i propose that if we talk about an ice-free arctic that we don not exclude regions arbitrarily so that the result meets our hypothesis.

perhaps i have to add that i'm open to discuss everything, i simply react to what i read and think that it's not absolutely correct or target leading. i do NOT claim to know better but i take the freedom to bring up a certain logic for others to consider while i can live well with other opinions as long as there is at least a kind of reason.

thing is that i agree with all those who predict a dramatical game change once most or big parts of the arctic ocean will be ice free in summer. this includes the probability that perhaps twice as much or more area that is currently freezing each winter will remain ice-free not that far out.

what i refuse to accept is that the arctic as per "entire arctic" which without further definition is meant IMO, will remain ice-free any time soon year-round.

if we start to exclude the areas that don't fit into our "idea" for a year-round-ice-free arcitc we are kind of cherry-picking or bending the facts so they fit in our claims and that is just not the way i think things should be approached, provided we are doing it to achieve something positive, be it to acquire most accurate knowledge and/or to tackle a problem and turn it into something better.

this is called an illusion IMO and illusions and wishful thinking are part of the reasons that brought us that far (down)

finally this is nothing personal of course, but i can only talk in reply to users that said something while my take on things is neither flawless nor personal.

magnamentis

I agree that the Arctic won’t be completely ice free year round anytime soon, but it will eventually happen, we are taking the climate out of ice age to hothouse

i agree on that one. i think the main differences are that some believe it will happen soon while i think it will take a lot of time still.

considering that some scientists FWIW predict sub 1 million km for the second half of this century in summer and then considering how much it will take form 1M km2 in summer to about no ice in winter i just didn't hear any convincing reasoning how this should be possible.

can be that reasoning lacks because there is no valid reason to believe that and could be that someone will sooner or later come up with good arguments.

further i sometimes think that those who "fight" so much for sensational shocking events forget to keep in mind that it would be much better for spaceship earth if it would take millenia rather than decades. i for my part will be happy if there will still be ice in winter the year a start my next journey to oblivion, mean pass away. as interesting as times are, there should be now wish to witness the consequences and the general global conditions once there will be zero ice year-round.

The central arctic basin will not be ice-free in winter for at least some centuries, IMHO.Take a look at the behavior of peripheral seas like the Chukchi and Bering, over time their ice-free season grows longer, but it's a very slow process and they still freeze over in winter. The Bering sea is very stormy, adjacent to the warm pacific, lies at only around 60 deg N, and still partially freezes over. So don't expect the north pole to stay ice-free year-round in your lifetime.

Logged

magnamentis

The central arctic basin will not be ice-free in winter for at least some centuries, IMHO.Take a look at the behavior of peripheral seas like the Chukchi and Bering, over time their ice-free season grows longer, but it's a very slow process and they still freeze over in winter. The Bering sea is very stormy, adjacent to the warm pacific, lies at only around 60 deg N, and still partially freezes over. So don't expect the north pole to stay ice-free year-round in your lifetime.

i thinks it's obvious that i share your opinion while which exact additonal part of the central arctic will first go ice free during winter is dependent on how exactly ocean (and wind) currents will develop over time when there will be generally less and less ice.

there is a certain possibility that a warm current will eventually take a path into the CAB and cause earlier than expected ice free winter than even in more southerly and peripheral regions adjacent to cold continents.

i'm by no means saying this will be the case but i think we cannot totally exclude the possibility, no matter how little probable it may appear and i think those who opt for a quick development into such direction here mean exactly that, only that this would still not make an ice-free arctic in winter.

if we talk about the arctic being ice free i say that each warm current has it's cold counterpart and that in one part of the arctic (one side if you prefer) there will always be a lot of ice.

You've said it before, and I asked: Is that some sort of natural law? That each warm current has it's cold counterpart? How and why?

To me this indicates a lack of understanding of how the big warm surface currents and the big cold bottom currents are tied together: The real counterpart of any warm surface current is a cold bottom current.

The image shows warm and cold currents in the North-Atlantic, both surface and deep. The warm currents are all on the surface, while the cold currents (with the exception of the narrow one running down the east coast of Greenland) are deep currents.

now i'd have to post a book to counter your statements, we'd have to go into density, salinity, when warm currents start to drop to the sea-floor to return south etc. but there are cold currents on the surface for sure, humbolt and many others, so the "all" is not correct and more time i'm not willing to spend on this topic. we can agree that we disagree and see what happens.

i tell you that none of us shall see an ice-free arctic in winter (arctic not north pole) and you have another opinion which to proof false would take years work of studies and combine them into an excerpt. this is just too much and won't change the future anyways, hence i propose to leave it at that for the moment, it simply doesn't matter who is right and the future will tell what is right/wil happen.

enjoy further

Well a simple explanation of what you meant by the twice-repeated statement that "each warm current has it's cold counterpart" would be fine. Did you mean that they run in tandem, i.e. for each warm current that flows into the Arctic, another cold current also flows into the Arctic? Easy question which you should be able to answer!

Perhaps we could pair them up: What is the cold surface current counterpart of the Gulf Stream in the North Atlantic? (Hint: there isn't one). I've helpfully provided a map of the ocean currents (again!), I for one am unable to see the "cold counterpart" surface current of the "Norwegian Atlantic Current" as named on the map. Note that on this map, the deep currents are helpfully shown with broken lines.

Another thing: I find it amazing that you seem to know what my opinion is! I've no idea whether we will see an effectively ice-free Arctic in my lifetime (or, to set the bar a bit lower, even open sea lanes through the arctic all year round for normal shipping). But I do think that if it does happen within the next several thousand years it could only happen because of increased inflows of warm ocean currents, and I do believe that this is a real possibility and that we are seeing it happen these last few years. Whether the warm currents will continue to creep further into the Arctic or not is the big question.

And this is where your spurious statement came from: You seem to be claiming that this could not happen because of some strange current symmetry where each warm current has a "cold counterpart".

So please make an effort at explaining what it is you are trying to claim!

I agree that the Arctic won’t be completely ice free year round anytime soon, but it will eventually happen, we are taking the climate out of ice age to hothouse

What is eventually? If its 200 years why is everyone fear-mongering on the subject ? The failed predictions of the past is one of the main reasons people are still debating AGW. Saying the arctic will be ice free in 50,30,20,10 years, sea level rise will disappear islands and roads on the coast will be under water and so many other predictions have failed.I agree that most are made by Politicians, celebrities and media (and some scientists looking for fame). Besides climate you can add in failed predictions on world famine,peak oil,population bomb and so many more. 200 years is a long time. Who knows what humanity can achieve in that time frame.

I agree that the Arctic won’t be completely ice free year round anytime soon, but it will eventually happen, we are taking the climate out of ice age to hothouse

What is eventually? If its 200 years why is everyone fear-mongering on the subject ? The failed predictions of the past is one of the main reasons people are still debating AGW. Saying the arctic will be ice free in 50,30,20,10 years, sea level rise will disappear islands and roads on the coast will be under water and so many other predictions have failed.I agree that most are made by Politicians, celebrities and media (and some scientists looking for fame). Besides climate you can add in failed predictions on world famine,peak oil,population bomb and so many more. 200 years is a long time. Who knows what humanity can achieve in that time frame.

magnamentis

90+ percent of additional heat trapped by increasing CO2 concentrations in the atmosphere is going into long-term storage in the oceans.

Does this not suggest that over time warm currents get warmer and cold currents less cold?

And that in turn is not good news for winter sea ice ?

put this way it's absolutely correct, question is if this "warmer" and "less cold" will suffice to compensate airtemps between -20C and -50C anytime soon.

since there's not much dispute about that sooner or later it can happen that the arctic will be ice-free year round (can, not will, we dont' know) this discussion is about WHEN and some say soon and i and others say in a few 100 years if at all.

now we only have to calculate how much energy has to be stored in the ocean to compensate for those extremely low winter temps, fed by land winds that can be down to -60C even.

so even if the entire system gets 20C warmer (air wise) we still have to see whether -30C or -20Cover a period of weeks will not be able to freeze at least parts of the oceans each winter.

as to currents (cold and warm) if the tone of that guy (not the quoted) get's slightly more condescending without reason i'll opt out, don't need to deal with things like that, one meeting in person would take care of that but it won't happen.

back on topic, there is and will be a warm in-flow and cooler out-flow. the cooler outflow will reach temps that are cold now and will be cold in the future while still being in "arctic waters" hence we shall for a long time to come have cold currents in the arctic that won't withstand winter temps to avoid ice-building for quite some time to come which is my entire point.

i never said it can't be, i only say two things:

a) it won't happen any time soon (soon like in decades)

b) we can't know whether it will ever happen but currently i'd say yes it sooner or later will happen. if things continue the way they do now which as well is not a given.

those are the points, the rest is noise based on righteousness and antipathy, both well knownand speaking for themselves.

EDIT:

the number of times i have to repeat basic statements to filter the distracting noise around it depends on feedbacks. if one looks at the quoted post and my direct answer to it there is no repetition. it's a normal exchange/discourse.

that changes only if someone, who is not, thinks he can play extra smart just because this place is in his mother tongue and not in another language which many of those intolerant players don't even speak. now one can ask how do i know about the "he is not" that's very simple, a wise or at least fair person would never ever attack that way in a discussion that is case oriented, just because the reasoning and/or opinion does not fit his own and without being totally off.

why should there be a thread with a question in the title if the answer would be clear and self-evident? that only would be the case if someone ask questions not to get answers but to get confirmation, a very widely spread evil indeed and then whoever dares to try to find an answerwill be discredited.

who ever does not agree with my reasoning and/or opinion or (language skills) and does that in a reasonable useful manner will receive either new reasons and/or a genuine thanks for the new knowledge he/she provided to me, many times been proven to be so MR. B

as to currents (cold and warm) if the tone of that guy (not the quoted) get's slightly more condescending without reason i'll opt out, don't need to deal with things like that, one meeting in person would take care of that but it won't happen.

So it's the personal attack now, along with a threat of bodily harm? How can you expect to make claims and not having to defend them, and instead start attacking and threatening people?

hat changes only if someone, who is not, thinks he can play extra smart just because this place is in his mother tongue and not in another language which many of those intolerant players don't even speak. now one can ask how do i know about the "he is not" that's very simple, a wise or at least fair person would never ever attack that way in a discussion that is case oriented, just because the reasoning and/or opinion does not fit his own and without being totally off.

And more of the same, personal attacks are symptomatic of a failed argument. And besides I'm not a native English speaker - I thought I made that clear?

And the point about spelling was that both you and gerantocrat had made stupid spelling mistakes because neither of you seemed to have read through what you had written before posting. But there is a big difference in that what gerantocrat writes actually makes sense.

But your original claim, that every warm ocean current has it's cold counterpart, can be deemed to be just something that you thought sounded good at the time? You did put it forward to dispute my point about possible changes in warm ocean currents as part of a normal debate, and then repeated it at a later point. Since you don't seem to be able to stand by your claim, I assume that you have acknowledged that my point has some merit.

To reiterate: The sea surface does not necessarily freeze even when temperatures are in the -20s or -30s centigrade, if there is a warm current keeping the surface above freezing (and remember that the surface of the sea needs to reach a temperature of abut -11 degrees centigrade to actually freeze over).

And we are seeing the northern extrusion of the Gulf Stream inching ever further north, it would seem by a hundred kilometers from year to year, and even moving in over deeper waters as A-Team pointed out yesterday, north of Svalbard. Earlier this summer it also seemed as if there was a creeping tongue of warm water moving along the Siberian seaboard.

But I can see from your musings that you have essentially accepted this point.

Logged

because a thing is eloquently expressed it should not be taken to be as necessarily trueSt. Augustine, Confessions V, 6

magnamentis

So it's the personal attack now, along with a threat of bodily harm? How can you expect to make claims and not having to defend them, and instead start attacking and threatening people?an see from your musings that you have essentially accepted this point.

people always understand what they want or what is along their own way of thinking.

it's almost painful how many word are abused and/or misinterpreted to meat your goals.

wich bodily harm?

if you refer to the personal meeting ? where did i mention any physical exchange of energies ?

i meant and always mean talking, nothing else and nothing i ever wrote would hint at that i support physical force, on the contrary, if i still really get into verbal fights with people, even people i love, like my dad, it's if they support war, weapons and any other means of physical harm to get what they want or in support of their favourites.

which personal attack:

i simply replied and referred to your low input as well as your trying to discredit me which with this post you do for the 3rd time in a row by accusing me of threatening you physically only because i believe that a personal meeting would make many things clear and while in each other sentence i offered a case oriented discussion.

however it's not me who started being personal if i may remind you about you mocking my language skills and i think i excessively tried to show and explain how a discussion of this kind can go without issues.

you disagree with my claims that some data are flawed, then state it and proof if you can, i shall gladly learn and listen.

if you have no proof, (you cannot proof something is right by taking that same something as a proof of itself) then just state your opinion and let's agree that we disagree, easy as that no problem for me, never was.

i had this discussions several times and there were such and such replies, some were reasonable and i reacted reasonably and all was good, some were trying to put me into a specific corner and then, even with a certain amount of ego-control, it's still there and at times i'd certainly like to post a bunch of a few thousands of pages i wrote in philosophy and astro physics just to make some stubborn haters aware who is on the other end but that's exactly not good which i try to keep things civil until giving up which i certainly do with this post. it's my last one on this topic, no matter what you call me, i'll not react anymore, i idid my best to bring this to fruition because beginnings can be difficult at times even between good guys. but i admit that i failed in this case.

So Long! have a happy life, no bad feeling will remain and if we ever meet i shall only say hello and talk nicely, hope it's clear enough

In regard to the idea of needing to overcome -50 to -20 degree C conditions to get sea water to freeze... One important thing to remember is that the current conditions are just that, the current conditions.

There is an all too easy bias that the way things are and the way things work now is the way they always have been and always have worked. This is clearly untrue.

We know from past geologic periods that the conditions supporting year round ocean temperatures of 20 C and atmospheric temperatures of 25 C. We do not have even good theories about how the earth’s systems worked to allow, let alone support, this.

We may very well be within decades of gaining first hand experience about how that works.

And if that isn’t terrifying for its global implications, I do not know what is.

So it's the personal attack now, along with a threat of bodily harm? How can you expect to make claims and not having to defend them, and instead start attacking and threatening people?an see from your musings that you have essentially accepted this point.

wich bodily harm?

if you refer to the personal meeting ? where did i mention any physical exchange of energies ?

Well, I might have misunderstood you. Normally, when people say something along the lines of what you said, they do actually mean having a physical fight! So perhaps better not say those kind of things.

But all in all, no harm done.

Logged

because a thing is eloquently expressed it should not be taken to be as necessarily trueSt. Augustine, Confessions V, 6

quoting from 132 above:"now we only have to calculate how much energy has to be stored in the ocean to compensate for those extremely low winter temps, fed by land winds that can be down to -60C even."

But only a part of the heat gets there and calculating this is rather complicated.

And the heat is there already but it can't get up without help.

I sort of think of the Arctic as a bastion. The edges are contested first. The Barentz is lost and both oceans are intruding further into the Arctic. With the ice being thin as it is now that should show up as a pattern the next couple of years? (see animation 2 in #2555 in 2018 Melting Season).

These areas will then warm up early creating water areas which can destroy more ice with wave action and warmer water (and if it warms up enough it should connect with warmer water below?).

In the old days most of the old ice was at some side so that side was stronger and the other weaker. But the Arctic was sort of covered.

Now at some point the CAB ice will more or less float freely and with the wrong direction that will destroy a lot of ice (and that is where most of the remaining extent is hiding now) . It might take multiple years.

A bit surprised at how many voted 2018-2019. I think i would go for the 2020-2040 bin and yes that is cheating.

I agree that the Arctic won’t be completely ice free year round anytime soon, but it will eventually happen, we are taking the climate out of ice age to hothouse

What is eventually? If its 200 years why is everyone fear-mongering on the subject ?

Because the Arctic Ocean need not be ice free to have a dramatic impact on the climate. We are already seeing the effect with blocking highs and persistent ridges causing extreme weather events all over the northern hemisphere.

The Bering Sea is almost perennially ice-free now, and I predict will be within 5 years, so that would be a bad example to pick to show that ice will continue to form in the CAB for a long time.

Look at the ocean around Svalbard. It routinely stays ice-free past 80-north. It is because it has a huge reservoir of heat constantly flowing in. Right now that reservoir is balanced out by the cold of the CAB, but when it is augmented by summer sun, we are going to see Svalbard-like conditions take over all of the deep, non-coastal parts of the Arctic.

The cold from land is no match for heat built up in water. Those -60C winds will quickly warm to around freezing if the heat is there in the water to support it. You simply won't see -30C in the CAB anymore if the water has a chance to soak up enough heat during the summer. It's not like the Hudson Bay, which is shallow, and can't build up much heat, and which will probably have ice in the winter until maybe after 2100. The ESS is shallow too, so I wouldn't be surprised to continue to see fast ice form there for many many decades in the winter. But I wouldn't expect this ice to go much farther than the continental shelf once the CAB gets a few ice-free summers from May onwards, and gets to warm up to 15C by each September. Heck, I wouldn't be surprised if it became possible to comfortably swim in the Arctic Ocean in some places in a few decades!

The cold from land is no match for heat built up in water. Those -60C winds will quickly warm to around freezing if the heat is there in the water to support it. You simply won't see -30C in the CAB anymore if the water has a chance to soak up enough heat during the summer. It's not like the Hudson Bay, which is shallow, and can't build up much heat, and which will probably have ice in the winter until maybe after 2100. The ESS is shallow too, so I wouldn't be surprised to continue to see fast ice form there for many many decades in the winter. But I wouldn't expect this ice to go much farther than the continental shelf once the CAB gets a few ice-free summers from May onwards, and gets to warm up to 15C by each September. Heck, I wouldn't be surprised if it became possible to comfortably swim in the Arctic Ocean in some places in a few decades!

There is already plenty of heat in the Arctic, about 30 meters below the surface.

Ive seen many projections like this showing the likely last areas to retain summer ice. But given the recent lift off from Cape Morris-Jessup, the lack of ice off Eastern Greenland and northern advancement of warm salty Atlantic water, I wonder have the models got it all wrong and the last preserve of ice will be a lot further west than northern Greenland.

Ive seen many projections like this showing the likely last areas to retain summer ice. But given the recent lift off from Cape Morris-Jessup, the lack of ice off Eastern Greenland and northern advancement of warm salty Atlantic water, I wonder have the models got it all wrong and the last preserve of ice will be a lot further west than northern Greenland.

We've talked about this a few times. I don't think, once ice goes below a certain threshold, that it will be close to land like on the National Geographic image (and other similar images). It would more likely just float around, and in reality just melt.

So below a certain threshold, we'd probably see the open Arctic ocean totally ice free.

Logged

because a thing is eloquently expressed it should not be taken to be as necessarily trueSt. Augustine, Confessions V, 6

I guess in winter we will still see ice near the coast, but it will get smaller and smaller and float away a lot of times - of course depending on wind conditions etc

I think the point was that once it gets small enough to move as a whole the random(ish) distribution of winds will take it out and it will not return. That's how random walk works and that's what we see in other shorelines as well. (This obviously holds true only for the larger chunk leaning against northern Greenland and CAB, not the ice soup inside the CAB)

While it's large enough to not really move as a whole, like now, the ice can retreat away by compression and it can and will get back over and over by decompression and refreezing.

Where's the threshold for that? I have no idea and that's one of the interesting things I'm waiting to see.

I have been Looking at that large area of remaining ice in the Beaufort Sea. This is not the first time we have seen such a separation or near separation of an area of ice from the main pack.I think we will see more and more of these separate ice patches in the future.

I am no longer envisioning the ice would retain a large central pack with clear fronts on all sides. Where long term the fronts would advance and the central pack would shrink, until the remaining ice is piled up along Greenland and Canada.

Instead I would propose that over years, we will see this central pack slowly dissolve into an increasing number of separate areas or concentrations of ice. Sort of like the breakup of a super continent into smaller, separate continents.

Eventually we will be tracking individual patches, for their own extent, area and concentration. Tracking the ups and downs of each, as we watch the sub-packs fade on their own schedules.

Thus the Blue Ocean Event will come when the few remaining scatterings of ice melt below the combined threashold. On that day there could be 3 or so separate areas of remaining ice in an otherwise blue ocean. And those remaining areas of ice could be anywhere in the Arctic Ocean.

It is time for the monthly update of my extrapolation when the extent [Extent], volume [Volumen] and thickness [Dicke] will reach zero. The extrapolation occured linearly and by a logarithmic function; the latter one constantly resulting in earlier times. See attached table.

It is time for the monthly update of my extrapolation when the extent [Extent], volume [Volumen] and thickness [Dicke] will reach zero. The extrapolation occured linearly and by a logarithmic function; the latter one constantly resulting in earlier times. See attached table.

Log function arrives at later date than linear for extent but earlier for volume and thickness. Why? Perhaps an example fit and extrapolation would help?

Also why a log function?

Curve seems more like gompertz to me and the models also seem to show gompertz shape. So why use a function that arrives at an earlier date than linear, particularly for volume?

My answers to your questions and remarks:1. Volume (and, in part, thickness) reduces faster than extent, therefore the non-linearity of the volume data is more expressed than the extent. This leads to extrapolation results with bigger differences between log and lin evaluation. For the winter and spring season the extent differences from year to year were slower in the 80s and 90s and have increased in the 00s but reduced in the 10s. This leads to the effect that the linear evaluation reaches zero a few years earlier than the log fit.2. I used the log function in addition to the linear because the deviation is slightly smaller in the log function. A quadratic extrapolation delivers almost the same results than the log evaluation.3. I have no expertise in Gompertz fits therefore I leave this to those who know how to deal with them correctly. But I confess that "Gompertz type fitted curves" look more closer to the volume data than linear, log or quadratic fits.

Generally: Extrapolations into the far future are scientifically nonsense. No-one knows which effect the first BOE in early autumn will have on the extent of the following months and years. With increasing GHG concentrations and changing ocean currents new mechanisms (at least new rates) in melting and re-freezing will be put into place.I did this evaluation for myself just to know whether - on the basis of a continuation of the trend of the last 40 years - it will take decades, centuries or millenia to reach zero and I decided to share this information with you.

My answers to your questions and remarks:1. Volume (and, in part, thickness) reduces faster than extent, therefore the non-linearity of the volume data is more expressed than the extent. This leads to extrapolation results with bigger differences between log and lin evaluation. For the winter and spring season the extent differences from year to year were slower in the 80s and 90s and have increased in the 00s but reduced in the 10s. This leads to the effect that the linear evaluation reaches zero a few years earlier than the log fit.2. I used the log function in addition to the linear because the deviation is slightly smaller in the log function. A quadratic extrapolation delivers almost the same results than the log evaluation.3. I have no expertise in Gompertz fits therefore I leave this to those who know how to deal with them correctly. But I confess that "Gompertz type fitted curves" look more closer to the volume data than linear, log or quadratic fits.

Generally: Extrapolations into the far future are scientifically nonsense. No-one knows which effect the first BOE in early autumn will have on the extent of the following months and years. With increasing GHG concentrations and changing ocean currents new mechanisms (at least new rates) in melting and re-freezing will be put into place.I did this evaluation for myself just to know whether - on the basis of a continuation of the trend of the last 40 years - it will take decades, centuries or millenia to reach zero and I decided to share this information with you.

Thanks for the answers.

Not sure I have much expertise with gompertz functions other than the forumla looks like:=parameter1*EXP(-EXP(Parameter 2*(year-Parameter3))) [+parameter4 if using 4 parameters)]

It is fairly easy to set up a spreadsheet to calculate 'sum of the errors squared' (or squareroot thereof) then optimise the parameters to minimise that total using a solver function/add-in.

I expect all your 'answers' will all be closer than my 4 parameter fits